A back door is attached to a vehicle such as a hatchback, a station wagon or a van for openably closing a luggage compartment at the rear of the vehicle. When a circumferential edge portion of the back door abuts a circumferential edge of an opening portion in the luggage compartment, the opening portion is closed. When the vehicle is driving or idling, the sympathetic vibration of the opening/closing member may be caused to generate uncomfortable noise or uncomfortable feeling. Various constructions have been proposed to suppress such uncomfortable noise. For example, there is proposed a construction which includes a cylinder whose interior is filled with a viscous fluid such as oil and a piston which is disposed slidably within the cylinder so as to damp vibration by restricting the sliding motion of the piston by the resistance of the viscous fluid.
Patent Literature 1 describes a vehicle opening/closing member stopper which positions a vehicle opening/closing member relative to a vehicle body and includes a damping member for damping vibration in an opening/closing direction of the vehicle opening/closing member upon its closure.
An embodiment shown in FIG. 8 in Patent Literature 1 includes a stopper main body secured to a tailgate panel and a hydraulic damper attached to a vehicle body panel. The hydraulic damper has a housing in which a fluid is sealed, a circular flange-shaped piston which is disposed slidably within the housing and in which an orifice is provided, a rod which projects from one surface of the piston, a seat which is provided at a distal end of the rod to contact and separate from the stopper main body, and a pair of springs which movably support the piston. The hydraulic damper is installed in a restriction member of hard rubber, and the restriction member is secured to the vehicle body panel by a securing member, whereby the hydraulic damper is attached to the vehicle body panel.
Then, when the tailgate or the vehicle body vibrates, the piston slides within the cylinder, and the vibration is damped by flowing resistance generated as the fluid passes through the orifice.
Patent Literature 2 describes a fluid sealed torque stopper which is disposed between an engine and a vehicle body so as to suppress the vibration of the engine. The torque stopper is made up of a pair half members which are joined together via a bulkhead and includes a cylinder having a fluid chamber and an air chamber, a piston rod which is inserted into the cylinder and which extends to an exterior of the cylinder at one end portion thereof, and a piston which is secured to the piston rod and disposed in the fluid chamber and which has an orifice. An end of the cylinder is coupled to the vehicle body side via a coupling portion, and the end portion of the piston rod which extends to the exterior of the cylinder is coupled to the engine side via a coupling portion. When the engine vibrates, the piston disposed in the fluid chamber of the cylinder slides, and the vibration of the engine is damped by resistance generated as the fluid passes through the orifice in the piston.
Patent Literature 3 describes a front fork having a vehicle-body-side tube, a wheel-side tube and a piston member. The vehicle-body-side tube is closed at an upper end and is opened at the other end. The wheel-side tube has a cylindrical shape, is disposed in the vehicle-body-side tube so as to rise and lower therein, and is opened at both upper and lower ends thereof. The piston member is disposed in the wheel-side tube so as to rise and lower therein.
A lower bearing member is coupled to an inside lower portion of the wheel-side tube, and an upper bearing member is coupled to an opening portion at the upper end of the wheel-side tube. An upper rod member which project from an upper surface of the piston member is supported by the upper bearing member, and a lower rod which projects from a lower surface of the piston member is supported by the lower bearing member. The upper rod is coupled to an upper wall of the vehicle-body-side tube at a distal end portion thereof, whereby the vehicle-body-side tube and the piston member are integrated with each other.
A spring is interposed between the upper wall and the upper bearing member inside the vehicle-body-side tube, so that the wheel-side tube is biased downwards relative to the vehicle-body-side tube. In addition, springs are interposed respectively between the upper bearing member and the piston member and between the piston member and the lower bearing member inside the wheel-side tube, so that the piston member is held in a predetermined position on an inner circumference of the wheel-side tube.
Then, when the wheel-side tube and the vehicle-body-side tube rise or lower relative to each other due to the vibration of the vehicle body side or the wheel side, the piston member rises or lowers within the wheel-side tube against the biasing force of the springs, and the piston member is slowed by oil which fills the wheel-side tube to thereby damp the vibrations.
An opening/closing member such as a trunk lid, a back door or the like is attached to a trunk or a rear luggage compartment of a vehicle so as to be opened and closed. The opening/closing member abuts a circumferential edge of an opening portion of the trunk or the luggage compartment so as to close the opening portion. In order to prevent the application of an excessive impact force or generation of striking noise due to striking of the trunk lid or the back door against the circumferential edge of the opening portion, a stopper may be disposed between the opening portion and the opening/closing member, so that the opening/closing member indirectly abuts the circumferential edge of the opening portion via this stopper, thereby restricting the rotational movement of the opening/closing member.
As such stopper, Patent Literature 4 describes an elastic structure which includes a base which is fixed to a trunk lid panel and an expandable/contractable cap member which is mounted thereon. The base has an insertion portion having a pair of locking claws and a holding portion which is provided continuously to the insertion portion. A pair of locking shoulder pieces are provided on a circumferential edge at an upper end of the holding portion, and an annular projection projects halfway along an axial direction of the holding portion. A movable shaft material is inserted into a center of the insertion portion and the holding portion so as to move vertically. A coil spring is interposed between a lower collar portion at a lower end of the movable shaft material and a step portion at a lower end of the holding portion, so that a lower end portion of the movable shaft material is biased so as to always project.
The cap member has a bottomed cylindrical shape, and is formed of a rubber material. An annular depressed groove is formed on an inner side of an upper end portion of the cap member, and an expandable/contractable accordion portion is formed halfway along an axial direction of the cap member. A semi-spherical elastic abutment portion is provided at a lower end portion of the cap member. Then, the upper end portion of the cap member is expanded so that the annular depressed groove of the cap member is securely fitted on the annular projection on an outer circumference of the holding portion, whereby the annular projection and the annular depressed groove are secured to each other elastically and tightly, and the cap member is mounted on the base with a gap between the base and the cap member sealed up closely. The locking claws of the insertion portion which is inserted into an attachment hole in the trunk lid panel engage with a rear side of the attachment hole, and the locking shoulder pieces of the holding portion engage with a front side of the attachment hole, whereby the elastic structure is attached to the trunk lid panel.